ORLANDO, Florida - US marine theme park SeaWorld will redesign the tank that holds its Killer Whales, creating a larger space for them, amid ongoing criticism over its treatment of the animals.

The plans were announced by SeaWorld CEO Jim Atchinson on Friday, who said that the redesigned tank would "transform the way visitors experience Killer Whales".

"Our guests will be able to walk alongside the whales as if they were at the shore, watch them interact at the depths found in the ocean, or a bird's eye view from above," he said.

SeaWorld has said that the plans are not in response to the release last year of the documentary film 'Black Fish', which investigated the deaths of several SeaWorld trainers and the treatment of the Killer Whales.

The film suggested that SeaWorld's treatment of the animals, and the fact that they are kept in captivity, provokes violent behaviour.

The film was released after the high-profile death of trainer Dawn Brancheau in front of an audience in 2010 sparked worldwide outrage. The trainer, who had 16 years of experience with orcas, was pulled into the tank and repeatedly dragged underwater and mutilated by a whale called Tilikum.

The new tank will be almost twice the size of its current orca tank, with 10 million gallons of water and a new depth of 50-feet (15m), according to the statement from SeaWorld, and will include larger viewing points for visitors.

PETA (People for the Ethical Treatment of Animals) has responded to the plans by saying that a "larger prison is still a prison". The animal rights group says that SeaWorld needs to move its Killer Whales to seaside sanctuaries so that they can experience the ocean again and hear their families.

SeaWorld has seen its profits slump in the past year since the company went public, with investors reportedly concerned about the long-term viability of SeaWorld's business model, which relies on the Killer Whale shows as its flagship attraction.